As a Program Grant this effort includes 14 interrelated projects developing data on the toxicology of organochlorine compounds and their metabolites, metals, organophosphates, carbamates, or alkaloids. The work on different projects ranges from study of molecular interactions and covalent binding through observations on intact mammals, and includes studies of effects on metabolism, membranes, tumor viruses, the immune system, and various enzyme complexes. The biophysical chemistry of xenobiotics is being examined and findings applied in predicting behavior of the agents in the field. This Program Grant is part of the program of the Environmental Health Sciences Center.